Tyres are designed to be run at the pressures the manufacturers specify thereby to achieve the longest life. Significant deviation from the specified pressure, whether above or below the specified pressure, causes excessive tyre wear. The actual pressure used depends to some extent on the load on the tyre.
It is well known that the pressure in a tyre varies with temperature. A tyre which is at optimum pressure when cold can be over optimum pressure when hot.
The present invention seeks to provide a device for controlling tyre pressure so that it remains at correct operating pressure.